Antislipping tile



G. N. JEPPSON.

ANTISLIPPING THE.

APPLICATION FILED APR.29, 1918.

1,402,296. Patepted Jan. 3, 1922 GEORGE NJEPPSO W/fnesses mass.

NH sears GEORGE N. JEPPSON, OF WORCESTER, MASSACHUSETTS,

PATENT cranes.

ASSIGNOR TO NORTON COMPANY, A CORPORATION OF MASSACHUSETTS.

ANTISLIPPING- TILE.

Specification of Letters Patent.

Patented J an. 3, 11922.

Application filed 'April 29, 1918. Serial No. 231,485.

in Antislipping Tiles, of which the followin is a full, clear, and exact specification,

y invention relates to anti-slipping or safety tread surfaces, and more particularly to ceramic tile, embodying therein granules of wear resisting anti-slipping material which give to the tread surface sufficient friction qualities to prevent a pedestrian slipping while walking thereon.

It is proposed to utilize-for an anti-slipping tread surface granules of previously molten alumina bonded together by a ceramic material in the form of a tile, which is laid as a smooth flooring surface and is particularly useful as a stair tread. As is known, this previously molten alumina, or what may be termed crystalline alumina, is exceedin ly hard, being about 9 on Mohs scale. Ifence its gripping action upon footgear will be pronounced, especially if the particles are of large size and project from the surface of the tile as a rough, uneven Furthermore, due to the ease with which such hard, projecting particles cut into shoe leather and so secure a firm hold thereon, a pedestrian cannot slip at all on such a surface. For ordinary anti-slipping purposes, however, it is desirable that the tread surface let the foot slip slightly to prevent too great a shock on the foot muscles. Therefore, these anti-slipping particles which project from the tile should be as small as possible, and yet give the desired antislipping characteristics. Furthermore, the smooth surfaced stone or tile, which is made of the finer grains, may be readil formed into a compact, dense structure which may be easily kept clean and sanitary.

It is found that substantially all of the wear on a stair tread occurs very close to the nose or forward end of the tread. F urthermore, it is the nose over which a pedestrian slips, hence this portion must possess such strong anti-slipping characteristics that there is no danger to one who is walking even carelessly on the stair. For this reason I find it necessary or desirable to utilize'for the nose of the tile coarse grained particles which will absolutely prevent slippnjg thereon.

f 1th these features injview, I have thereore vision of a ceramic bonded tile of hard, wear resisting granular particles, the top surface of which comprises an area which is comparatively smooth and yet satisfactory for ordinary anti-slipping purposes and a rough nose portion of great frictional characteristics which will absolutely prevent a pedestrian slipping thereon.

lVith this and other objects in view, as will appear from the accompanying disclosure, my lnvention resides in the combination of parts set forth in the accompanying description, and covered by the claims appended hereto.

Referring to the drawings in which like numerals designate like parts:

Fig. 1 is a perspective View top and nose of a tile; and

Fig. 2 is a similar perspective View showing tile.

showing the Of the materials which approach the diamond in hardness there are but few which may be termed extremely hard and wear resisting or durable under the action of footwear, and these include silicon carbide and previously molten or crystalline alumina.

These wear-resisting, anti-slipping granules must be bonded together into a unitary mass by ceramic or equivalent materials which are hard, durable and tenacious as well as capable of holdin the grains rigidly in place under the or inary shocks and abrasions of pedestrian wear and yet permitting them to be broken away ultimately before they become too smooth to prevent slipping thereon. For this bond, I preferably utilize a ceramic material which will vitrify to a porcelain-like mass or fuse to a glassy bond. This bond may comprise -var1ous' ceramic ingredients and be compounded as desired by workers skilled in the art. As a specific example of one type of bond well adapted for my purposes, I find it feasible to use a mixture of slip clay, ball clay, feldspar and whiting.

To make such a tile most serviceable for a platform edge or stair tread, ,as' above explained, I give the nose portion a rough surface capable of preventing slipping, while the under-side of a similarly constructed for an object of my invention the prothe rear portion of the tread has a finer, smoother surface. I have illustrated in the drawings a specific embodiment of my in vention comprising a treadblock 1 which may be of any suitable shape but preferably a flat plate havinga'rectangular surface. That portion of the block or tile which is to serve as the nose of the stair tread or the upper forward corner portion thereof may be rounded off as at 2. The bottom face 3 of the tile is preferably provided with grooves '4 or other suitable means, such as an irregular surface or perforations for screws or bolts, to hold the tile in concrete or on other foundation material.

In order to make the rough and fine surfaces, I may make the body portions of large and fine granules respectively, in which case I proceed along the following line. A mold having its bottom corresponding with the shape of the upper face 5 of the tile block is provided. A partition 6 (diagrammatically shown in Fig. 2 in phantom view) is located at the proper position in order that the coarse and the fine parts of the tile may be formed in separate operations. Then the forward or nose end of the mold is filled with a plastic composition of previously fused granular particles of alumina, for example, preferably of grain sizes of 20 to 36 mesh, and if desired incorporated with smaller grains to give density and compactness, mixed with water and a suitable ceramic bonding agent, such as a glass fusing clay bond of feldspar, slip clay, ball clay and whiting. Similarly, another plastic mixture of the crystalline alumina of finer grain sizes and a clay bond is poured into the rear end of the mold, after which the partition may be withdrawn and the whole subjected to pressure to compact the mass and give it the required density. The grooves 4 may he formed in the press. After drying, the tile is burned slowly at a temperature approximately 1300 C. for a suitable time. and under the proper conditions to vitrify or glass fuse the bond, it being desirable to continue the heating process for about 100 hours. The subsequent cooling operation is continued for a similar length of time. The burning operation unites the two parts of the tile into a unitary body. iv

- The size of grain utilized in the rear portion of the tile may be as desired, but I find that the very finest grains are suitable for this purpose. However it is obvious that the sizes of grain to be chosen for the two parts of the tile depend upon the intended use for the tread and its location. The deniaoaaea sity and compactness of the mass may be controlled by modifying the bond in accord: ance with methods well known in the ocramic art and by varying the sizes of the granules. By mixing fine grains with the coarser particles, and by using a number of different sizes of grain, an desired density up to a maximum may be 0 tained.

I have thus provided a ceramic safety tile having hard, wear resisting particles of large size and very efiective anti-slipping characteristics, located where the tread will e exposed to maximum wear or where a pedestrian is most liable to lose his foothold and slip, and having smaller particles of anti-slipping granular material in positions less exposed to wear and where safety considerations are not as important.

I claim as my invention 1. A safety tread tile comprising hard, wear-resisting granules and a bonding medium therefor intimately bonded and forming an integral structure, the nose portion of the tread surface having coarser grains of higher anti-slipping characteristics than the remainder of said surface.

2. A. safety tread tile comprising granules of a hardness of 9 or more and a ceramic bond united as a unitary mass, the grain sizes in that portion of the, tread surface intended for heavy wear averaging larger than those in the remainder of the block.

3. In a safety tread tile, a portion, comprising granules of crystalline alumina bonded into a unitary mass, adapted to prevent slipping thereon. and a second portion integral therewith and exposed to traffic wear, comprising a bonded mass of wear-resisting anti-slipping material, which has lower anti-slipping characteristics than the first portion.

4. An anti-slipping tread tile comprising a round nosed, fiat plate of ceramic bonded crystalline alumina grain, the nose portion containing large alumina granules capable of resisting wear and slipping tendencies and the rear body portion containing smaller granules and having a smoother surface than the nose. i

5. An anti-slipping tread tile comprising a fiat plate of ceramic bonded granular alumina having a rounded nose and a groove to cooperate with a foundation to hold the tile in place, the nose'portion of the plate containing larger alumina granules than the rear portion.

Signed at'Worcester, Massachusetts, this 27th day of April, 1918.

GEORGE N. JE'PPSON. 

